1. Field of the Invention
The present invention relates to a device control apparatus, such as a computer system, a consumer gaming machine, and so forth, which is connected to at least one device.
2. Description of the Related Art
Generally, a computer system, a consumer gaming machine, and so forth, is connected to a plurality of devices, including an input device, such as a mouse, a keyboard, a game controller, and so forth, and an external disc device, such as a DVD drive, and so forth.
In recent years, a problematic technique for eavesdrop for cheating a signal relating to an access made by the CPU of a computer system with respect to such a device becomes a serious issue.
For example, in data encryption, which is carried out by a CPU by reading plain data from a memory, processing the plain data, and storing the processed data into the memory, there is a possibility that the plain data before encryption may be stolen by reading out the data from signal lines through which the CPU read out the data from the memory device.
In order to cope with the above situation, there is proposed a technique for encrypting data being exchanged between the device and the CPU. In such a technique, a different encryption key is assigned to each device. Also, in order to avoid a situation in which encryption in all apparatuses would becomes invalidated should an encryption key be stolen, for example, a different encryption key may be used for each apparatus.
However, supposing that a different encryption key is used for each apparatus, the number of encryption keys which would be necessary in communication with the devices to access would be required to be issued for each apparatus and set in the CPU. This results in increased burden in manufacturing, and therefore, manufacturing efficiency cannot be improved.
It should be noted that a technique for eliminating the need to assign an individual encryption key to software to be distributed is disclosed in Japanese Patent Laid-open Publication No. Hei 11-282667.